The present invention relates to a method and apparatus for heat treating a continuous strand of food product. More particularly, the invention relates to a product and process for efficiently and cost effectively blanching or cooking strands of fresh pasta product.
Typically, blanching of pasta strands may be performed on conveyor belts in a long flat unit having a length of about 20 to 30 meters. Such a unit takes up a great deal of space and requires a large amount of energy to regulate the temperature of the aqueous bath.
Compact blanching devices have been. developed for blanching or cooking pasta strands without using conveyor belts in the tank. This reduces the space required in the factory by 800% to 1000%. Various of these devices are, described in the art as follows.
U.S. Pat. No. 2,905,105 to Lombi relates to a manicotti machine having a stack of closely spaced, parallel conveyors, wherein the top run of the endless belts of adjacent conveyors travel in opposite directions.
U.S. Pat. No. 4,522,217 to D""Alterio discloses paired conveyor belts with zigzag travel to treat food material in a liquid bath.
U.S. Pat. No. 4,745,935 to D""Alterio discloses submerged nozzles in a two-zone bath where conveyor belts pass through a slotted wall.
EP Patent No. 0 640 293 to Askman relates to a process for blanching pasta that includes feeding a pasta strand and hot water to an inlet of a pipe and conveying the pasta strands and hot water through the pipe. This process is adapted only for relatively thin strands, such as spaghetti strands.
EP Patent No. 0 428 763 to Larsen describes a blanching tank having positioned therein at least one substantially stationary roller and at least one movable roller capable of reciprocating vertically from a position above to a position below the substantially stationary roller. Although this device significantly reduces the amount of floor space and the volume of liquid medium to be heated, there still remain a number of shortcomings.
During blanching, pasta in particular has a tendency to expand both in length and width as it moves through the liquid medium due to the water absorption and the modifications of the texture of the pasta. Therefore, the roller systems of the prior art impart stretching and friction on the pasta when the system adjusts itself in response to the pasta expansion. The risk of breakage of the pasta strand cannot be totally eliminated despite the fact that sophisticated control systems can be installed to ensure satisfactory running conditions. In any event, as it is necessary to ensure a maximum degree of safety and control, such conventional systems remain complicated and costly and usually require constant human control to stop the apparatus when facing the first signs of malfunction. Since pasta strands can be easily and rapidly submitted to high tensions, even during a very short period of time, that is highly dependent on the mechanical elements and the response delay of the control system, the devices of the prior art have relatively low and recognized maximum speed limits to guarantee smooth operational conditions.
Thus, it is desired to provide an apparatus and method capable of more efficiently and cost effectively cooking or blanching food products, such as pasta, while minimizing or avoiding breakage or other undesirable damage to the food product.
The invention relates to an apparatus for heat treating a food product including a vessel for containing a fluid heating medium, and a device immersed within the fluid heating medium for transporting each strand along a travel path in a main direction through the heating medium, wherein the device includes a plurality of suspenders arranged to hang each strand freely in static position relative to the suspenders so as to form a plurality of freely suspended loops of strands in the fluid heating medium.
In one embodiment, the plurality of suspenders is attached to the device for travel in a continuous, substantially horizontal direction within the fluid heating medium, whereby the suspenders are arranged in a direction substantially orthogonal to the substantially horizontal direction of travel when the at least one strand is attached to the device.
In another embodiment, each suspender formed a U-shaped member having free ends forming bearing members and side arms attached to the device, while leaving a central area for loops of food product to hang freely therebetween, with the bearing members adapted to engage at least a portion of each strand of food product when the strand enters the fluid heating medium, transport portions of each strand within the fluid heating medium, and release each portion after exiting the fluid heating medium.
In a further embodiment, the bearing members extend substantially transversally from a longitudinal path along a width sufficient to receive each strand. In an additional embodiment, the bearing members include protrusions that extend in at least two distinct directions to engage each strand. In another embodiment, the protrusions are distributed in a divergent configuration along an angular path xcex8 of about 90xc2x0 to 220xc2x0. In still another embodiment, the apparatus further includes an inlet device to transport each strand within the fluid heating medium, and an outlet device to transport each strand away from the fluid heating medium.
In another embodiment, the apparatus further includes at least one sensing device arranged for sensing a position of a portion of each strand in a predetermined area and a controlling device for receiving input from the sensing device and having an output for adjusting the speed of each strand so as to maintain the position of the strand in the predetermined area at a pre-set positioning reference. In another embodiment, the sensing device is positioned for sensing the position of each strand in an area located between the outlet of the food strand from the fluid heating medium and the outlet device. In still another embodiment, the sensing device includes an ultrasonic transmitter that measures a distance between the portion of each strand and the transmitter, and the controlling device compares the measured distance with a pre-set distance of reference. In still another embodiment, the device provides a nominal production rate of each strand within the fluid heating medium of about 3 to about 20 meters per minute. In a preferred embodiment, the nominal production rate of each strand within fluid heating medium is about 8 to 16 meters per minute. Preferably, the each strand includes pasta.
The invention also relates to a process for cooking at least one strand of food product which includes forming each strand in a free suspended loop extending in a first direction, and conveying each food strand longitudinally through a liquid medium in a direction at least substantially orthogonal to the first direction, wherein the conveying longitudinally is of sufficient length to cook each strand.
In one embodiment, a substantially constant amount of each strand is maintained in the liquid medium by sensing a position of the at least one strand and controlling the position of each strand according to a pre-set position of reference. In another embodiment, each strand includes a flat, filled, or thin strand of pasta, or a combination thereof. Preferably, the cooking is conducted for a sufficient time to includes blanch the food product. .
The invention further relates to a process for cooking at least one strand of food product, including conveying each food strand through a blanching tank on a device immersed within the tank, the device including means for allowing the food strand to hang on a plurality of bearing means of the device, while forming a plurality of free suspended loops of food strand between each adjacent bearing means when operatively arranged to hang the food strand. In a preferred embodiment, a plurality food strands is hung in parallel on the bearing means.